Generally, an electric vehicle uses electricity as a fuel and uses a battery as a power source, unlike a gasoline engine. Such an electric vehicle has recently been spotlighted as a pollution-free vehicle, which does not discharge exhaust gas. An electric vehicle has good motor characteristics and uses a reducer with a single gear ratio to adjust the speed of the vehicle.
Conventionally, when only motor torque is utilized or when only an electric reducer is used, motor capacity relatively increases, and production costs increase accordingly. Therefore, there is a need to solve the above problems.
The background of the present invention is disclosed in Korean Patent Publication No. 2004-0033701 (published on Apr. 28, 2004 and entitled “TRANSMISSION OF HYBRID ELECTRIC VEHICLE).